Publications by authors named "D Flahaut"

Article Synopsis
  • Li-ion battery performance depends on the microstructure and interfaces of composite electrodes, with the binder playing a key role in maintaining mechanical integrity.
  • The traditional binder, poly(vinylidenefluoride) (PVDF), has drawbacks like toxic solvent use, low electric conductivity, and weak interactions with materials.
  • This study proposes using Poly(3,4-ethylenedioxythiophene):poly[(4-styrenesulfonyl)(trifluoromethylsulfonyl) imide] (PEDOT:PSSTFSI) as a better alternative, enhancing conductivity and lithium movement, leading to improved battery performance and longevity.
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Article Synopsis
  • - Li(NiCoAl)O is a long-time lithium-ion battery cathode known for its high energy capacity and density but moderate power, making it a reliable choice for energy storage.
  • - Atomic layer fluorination (ALF) with XeF is used to enhance the battery's cyclability by creating a protective fluorinated layer with minimal fluorine content (only 1.4 wt%).
  • - Various characterization techniques show that adding fluorine improves the electrochemical performance of Li(NiCoAl)O, enhancing its cyclability, polarization, and rate capability, with further insights into these benefits obtained from infrared spectroscopy and gas chromatography.
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Article Synopsis
  • A manganese-cobalt asbolane material was synthesized from birnessite using low-temperature cationic exchange with cobalt nitrate, enabling a high active mass loading for use in supercapacitors.
  • The material features a unique structure with MnO-type slabs and Co(OH) islands, confirmed through electronic transmission microscopy, showing two interlocking hexagonal sublattices.
  • Electrochemical tests demonstrated impressive capacitance of up to 180 F g, revealing effective charge storage mechanisms synergizing the properties of both components, along with promising long-term performance durability.
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In the energy storage field, an electrode material must possess both good ionic and electronic conductivities to perform well, especially when high power is needed. In this context, the development of composite electrode materials combining an electrochemically active and good ionic conductor phase with an electronic conductor appears as a perfectly adapted approach to generate a synergetic effect and optimize the energy storage performance. In this work, three layered MnO phases with various morphologies (veils, nanoplatelets and microplatelets) were combined with electronic conductor cobalt oxyhydroxides with different platelet sizes (∼20 nm 70 nm wide), to synthesize 6 different composites by exfoliation and restacking processes.

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Article Synopsis
  • The layered oxide LiNiMnCoO is a promising electrode material for Li-ion batteries, offering good capacity, stability, and cycling performance, potentially applicable in all-solid-state batteries.
  • Three samples of varying particle sizes (240 nm, 810 nm, and 2.1 μm) were synthesized using coprecipitation and high-temperature solid-state reaction, maintaining an ideal 2D layered structure.
  • The electrochemical properties were tested in both traditional liquid and gel electrolytes, while the interface degradation was analyzed using X-ray photoelectron spectroscopy to assess the impact of particle size and electrolyte type.
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